Demand for energy-efficient Solid State Lighting (SSL) based lighting devices is driven by various factors such as improved energy efficiency, enhanced product life, lower maintenance costs, and reduced environmental impact. An example of the SSL based lighting devices that uses inorganic semiconductors is a Light Emitting Diode (LED) lighting device.
In a lighting system, a constant-current driver circuitry is provided for conversion of AC power input into constant-current power output. The constant-current DC power output is subsequently delivered to the LED lighting devices. As the conversion from AC line voltage to milliamperes of constant DC current is critical to the functioning of the LED lighting devices, efficiency of the driver circuitry is very important. Performance quality of the constant-current driver circuitry is determined by several factors such as input AC voltage range, line surge protection, conversion to output DC constant-current and most importantly, the output power requirement. The efficiency of the LED driver circuitry is critically dependent on output LED load and how wide the range of input voltage.
The impact of loss in efficiency of a power supply unit will increase power usage, reduced light output per watts of power usage and reduce reliability of the power supply unit and increase chances of field failures. The loss in efficiency is dissipated in form of heat and heat in electronic circuitry is one of the main contributors to reduction in life expectancy of electronic components. In order to improve reliability and increase Mean time between failures (MTBF) of the drivers lighting system efficiency must be increased and losses reduced.
Generally, a LED power supply driver is disposed inside or outside of the LED lighting device. Such an arrangement decreases the distance between power supply and a LED lighting device base thereby, preventing an output power drop from an output of the power supply to the LED lighting device base. The production and installation can be more convenient if one or more than one power supply is disposed in a groove of a main heat-dissipating outer cover of the power supply.
It is possible to design power drivers to be optimized for output LED load and a smaller range of input voltage; however, since LED fixtures inherently built to meet lumen output load the concept of customized drivers for different LED loads would become unpractical and expensive. This invention provides an innovative solution. It provides modularity and creates highly manageable and efficient product.
In light of the above discussion, there is a need for an improvement in LED power supply system in order to optimize output drive capability of the LED power supply system over smaller ranges of power input and driver loads.